package com.myproject.source.image;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import com.myproject.source.R;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.widget.ImageView;

public class ImageLoader {
	 MemoryCache memoryCache=new MemoryCache();
	    FileCache fileCache;
	    private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
	    ExecutorService executorService;
	    
	    public ImageLoader(Context context){
	        fileCache=new FileCache(context);
	        executorService=Executors.newFixedThreadPool(5);
	    }
	    
	    final int stub_id=R.drawable.stub ;
	    public void DisplayImage(String url, ImageView imageView)
	    {
	        imageViews.put(imageView, url);
	        Bitmap bitmap=memoryCache.get(url);
	        if(bitmap!=null)
	            imageView.setImageBitmap(bitmap);
	        else
	        {
	            queuePhoto(url, imageView);
	            imageView.setImageResource(stub_id);
	        }
	    }
	        
	    private void queuePhoto(String url, ImageView imageView)
	    {
	        PhotoToLoad p=new PhotoToLoad(url, imageView);
	        executorService.submit(new PhotosLoader(p));
	    }
	    
	    private Bitmap getBitmap(String url)
	    {
	        File f=fileCache.getFile(url);
	        
	        //from SD cache
	        Bitmap b = decodeFile(f);
	        if(b!=null)
	            return b;
	        
	        //from web
	        try {
	            Bitmap bitmap=null;
	            URL imageUrl = new URL(url);
	            HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();
	            conn.setConnectTimeout(30000);
	            conn.setReadTimeout(30000);
	            conn.setInstanceFollowRedirects(true);
	            InputStream is=conn.getInputStream();
	            OutputStream os = new FileOutputStream(f);
	            Utils.CopyStream(is, os);
	            os.close();
	            bitmap = decodeFile(f);
	            return bitmap;
	        } catch (Exception ex){
	           ex.printStackTrace();
	           return null;
	        }
	    }

	    //decodes image and scales it to reduce memory consumption
	    private Bitmap decodeFile(File f){
	        try {
	            //decode image size
	            BitmapFactory.Options o = new BitmapFactory.Options();
	            o.inJustDecodeBounds = true;
	            BitmapFactory.decodeStream(new FileInputStream(f),null,o);
	            
	            //Find the correct scale value. It should be the power of 2.
	            final int REQUIRED_SIZE=100;
	            int width_tmp=o.outWidth, height_tmp=o.outHeight;
	            int scale=1;
	            while(true){
	                if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
	                    break;
	                width_tmp/=2;
	                height_tmp/=2;
	                scale*=2;
	            }
	            
	            //decode with inSampleSize
	            BitmapFactory.Options o2 = new BitmapFactory.Options();
	            o2.inSampleSize=scale;
	            return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
	        } catch (FileNotFoundException e) {}
	        return null;
	    }
	    
	    //Task for the queue
	    private class PhotoToLoad
	    {
	        public String url;
	        public ImageView imageView;
	        public PhotoToLoad(String u, ImageView i){
	            url=u;
	            imageView=i;
	        }
	    }
	    
	    class PhotosLoader implements Runnable {
	        PhotoToLoad photoToLoad;
	        PhotosLoader(PhotoToLoad photoToLoad){
	            this.photoToLoad=photoToLoad;
	        }
	        

	        public void run() {
	            if(imageViewReused(photoToLoad))
	                return;
	            Bitmap bmp=getBitmap(photoToLoad.url);
	            memoryCache.put(photoToLoad.url, bmp);
	            if(imageViewReused(photoToLoad))	
	                return;
	            BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad);
	            Activity a=(Activity)photoToLoad.imageView.getContext();
	            a.runOnUiThread(bd);
	        }
	    }
	    
	    boolean imageViewReused(PhotoToLoad photoToLoad){
	        String tag=imageViews.get(photoToLoad.imageView);
	        if(tag==null || !tag.equals(photoToLoad.url))
	            return true;
	        return false;
	    }
	    
	    //Used to display bitmap in the UI thread
	    class BitmapDisplayer implements Runnable
	    {
	        Bitmap bitmap;
	        PhotoToLoad photoToLoad;
	        public BitmapDisplayer(Bitmap b, PhotoToLoad p){bitmap=b;photoToLoad=p;}
	        public void run()
	        {
	            if(imageViewReused(photoToLoad))
	                return;
	            if(bitmap!=null)
	                photoToLoad.imageView.setImageBitmap(bitmap);
	            else
	                photoToLoad.imageView.setImageResource(stub_id);
	        }
	    }

	    public void clearCache() {
	        memoryCache.clear();
	        fileCache.clear();
	    }
}
